Let’s start with the simplest oval of track. If you don’t have any points on your layout then you will only need two wires. Take a look at your controller (or, in some cases, controller hub) and you will see some holes. The wording surrounding these holes may vary, but they all do the same thing – one will be a positive feed while the other is a negative feed; in other words ‘out’ and ‘in’, or ‘+’ and ‘–’. The electricity will flow out of one hole down the wire and into one rail, through any locomotive that is on there, back down the other rail, along the wire and return into the controller or controller hub, completing the loop (circuit). If there are no locomotives on the layout the circuit is not complete and the electricity will not flow. It’s important to ensure that the positive and negative rails never touch each other. If this happens you’ll get a short circuit, nothing will work and it has the potential to damage your expensive models. The easiest way to avoid short circuits is to take your time and to colour-code your wires. Using a different colour for different feeds is the best way to avoid a mis-wiring, as well as being the easiest way to discover any faults. Never wire your layout entirely with cables of the same colour – it will make faults practically impossible to find! For large layouts, the most reliable way to do the wiring is to have two thicker ‘bus wires’ that run along the length of the layout with dropper wires feeding off them. If you use a lot of thin wires you may find that the resistance in the wire is too high and the current will drop below a sufficient level at some points of the layout.